The Card

The single VSA-100 chip
on the Voodoo4 4500 features the same 128-bit path to its local memory as each
individual chip on the Voodoo5 5500 does, the only difference here being that
the Voodoo4 4500 features exactly half the memory as its older brother. With
32MB of SDRAM dedicated to the single VSA-100 chip, the Voodoo4 4500 has exactly
half the memory storage and memory bandwidth of the 5500 since each chip on
the 5500 gets a dedicated 128-bit path to 32MB of the total 64MB on-board.
At the same time, since there is only a single VSA-100 chip on the Voodoo4 4500,
it gets all of the memory bandwidth to itself.

The VSA-100 chip is clocked
at 166MHz and since the memory clock is synchronous with the core clock, the
32MB of SDRAM is also clocked at 166MHz. Our evaluation card featured four
8MB 6ns Toshiba SDRAM chips. With a 6ns rating, these chips carry a 166MHz
operating frequency, meaning that you shouldn’t expect to be able to push them
too much higher than their original 166MHz clock frequency. This also means
that at 166MHz, the Voodoo4 4500 has a total of 2.7GB/s of peak available memory
bandwidth, which is equivalent to the memory bandwidth on the Radeon SDR (almost),
the GeForce 256 (SDR) and the GeForce2 MX.

As we mentioned before,
the VSA-100 can render two single textured pixels per clock or one dual textured
pixel per clock, the latter being the more informative number when dealing with
today’s games. The 166MHz core clock frequency translates into a dual textured
fill rate of 166 megapixels per second or 333 megatexels per second. Since
the Voodoo4 4500 only features one of these VSA-100 chips, it takes the crown
as having the lowest fillrate out of all other boards in its class, with the
GeForce 256 SDR boasting a 480 megatexels/s fillrate and the Radeon SDR boasting
a 1 gigatexel/s fill rate. At the same time, you’ll have to realize that memory
bandwidth limitations will kick in before either of those theoretical maximum
fill rates will kick in during real world gameplay.

Unlike its larger brother,
the Voodoo4 4500 does not feature an external power connector and is powered
completely from the AGP or PCI slot. The same AAVID heatsink/fan that is found
on each of the two VSA-100s on the Voodoo5 5500 is found on the single VSA-100
on the Voodoo4. It is attached to the chip using thermal glue.

So what you’re essentially
getting with the Voodoo4 4500 is a Voodoo5 5500 with one chip disabled (which
also disables half of the memory on the card). However 3dfx has made a few
changes to the Voodoo4 that separate it from the Voodoo5 5500. We already mentioned
that there is no +5V power connector on the card itself since its only using
a single VSA-100 chip. This helps to reduce cost, as does the fact that the
board is physically smaller than the Voodoo5 5500. The only other thing to
change with the Voodoo4 is the fact that 3dfx only allows up to 2-sample FSAA.
The reason for this is simple: by enabling 2-sample FSAA, you already cut the
Voodoo4 4500’s fill rate in half; by allowing users to enabled 4-sample FSAA
the fill rate would be cut into a fourth and very few games would be playable.
While there is most likely a hack to get around this limitation and enable 4-sample
FSAA, there’s really no reason as to why the Voodoo4 4500 simply doesn’t have
the fill rate to make that a viable option.

For more information on
the various FSAA settings and how they compare among 3dfx, NVIDIA and ATI, please
read our FSAA Comparison, as we will not focus
on FSAA in this review.